1. Field of the Invention
The present invention relates to a recording tape cartridge which rotatably accommodates a single reel on which a recording tape, such as a magnetic tape or the like, is wound.
2. Description of the Related Art
Recording tapes such as magnetic tapes and the like are used as external recording media for computers and the like. The recording surface area of a recording tape is large, and the recording tape is used mainly for back-up of a large quantity of information. Thus, it is desirable to prevent dust from adhering to the recording tape, and for the space for accommodating the recording tape at the time of storage thereof to be small.
Thus, a recording tape cartridge, in which a recording tape is wound on a single reel and which rotatably accommodates the reel within a case, is used. In this way, owing to the case, dust can be prevented from adhering to the recording tape. Moreover, the accommodating space during storage can be made to be substantially half that of a structure having two reels which take-up a recording tape at the time information is to be recorded onto or played back from the recording tape.
In such a recording tape cartridge, while the recording tape is pulled-out from the case within a drive device, information is recorded onto the recording tape or information recorded on the recording tape is played back by a recording/playback head within the drive device. Hereinafter, a structure by which the drive device pulls out the recording tape will be described with reference to FIG. 12.
In a recording tape cartridge 200, an opening 206 for pulling-out of a recording tape 204 is formed in a case 202 which accommodates an unillustrated reel (see FIG. 12). A leader block 208 is connected to the distal end of the recording tape 204. The leader block 208 is held within the case 202 so as to face the opening 206, and, in this state, closes the opening 206.
An engaging concave portion 210 is provided at the distal end of the leader block 208. The lower portion of the engaging concave portion 210 is formed as a large diameter concave portion 218, whose opening 216 is narrowed by engagement portions 212, 214. A pair of upper and lower cut-out portions 220, which expose the engaging concave portion 210 (the large diameter concave portion 218) upwardly and downwardly, are provided above and below and communicate with the opening 206 of the case 202.
A pull-out device 222 is provided within the drive device. The pull-out device 222 has an arm 224, a rod 226, and a large diameter portion 228. The arm 224 is guided by an unillustrated cam groove and can move in a predetermined direction. The rod 226 can enter into the engaging concave portion 210 through the opening 216. The large diameter portion 228 is provided at the distal end of the rod 226, and cannot pass through the opening 216. The diameter of the large diameter portion 228 is slightly smaller than that of the large diameter concave portion 218.
When the recording tape cartridge 200 is loaded into the drive device, accompanying this loading operation, the rod 226 of the pull-out device 222 enters into the engaging concave portion 210 of the leader block 208. Then, when the recording tape cartridge 200 moves downward, the large diameter portion 228 of the pull-out device 222 enters into the large diameter concave portion 218 of the leader block 208 from beneath.
In this state, when the arm 224 of the pull-out device 222 moves along a horizontal plane, the leader block 208 separates from the case 202 while the engagement portions 212, 214 of the leader block 208 engage with the large diameter portion 228 and are held at the pull-out device 222. In this way, the recording tape 204 connected to the leader block 208 is pulled-out from the case 202.
The leader block 208 is fit in (accommodated in) a fit-in portion provided at a reel hub of a take-up reel of the drive device by the pull-out device 222. An end surface 208A, which is at the side opposite the engaging concave portion 210, forms the outer peripheral surface of the reel hub and a take-up surface along which the recording tape is taken-up. In this state, when the take-up reel is driven to rotate, the recording tape is successively pulled-out from the case while being taken-up onto the take-up surface. Information is recorded onto or played back from the recording tape by a recording/playback head provided along a predetermined tape path.
However, in the above-described conventional recording tape cartridge 200, the large diameter concave portion 218, into which the large diameter portion 228 of the pull-out device 222 enters, must be provided at the leader block 208. Accordingly, a problem arises in that the width of the leader block 208 increases.
If the width of the leader block 208 is large, the position at which the leader block 208 is held at the case 202 is limited, and there are fewer degrees of freedom in designing the recording tape cartridge 200. Moreover, the opening width of the fit-in portion of the aforementioned reel hub must be made large, and this is a cause of a step arising at the take-up surface.
Recording tape cartridges which are equipped with small, solid-cylindrical leader pins instead of the leader block 208 are known. One example is the cartridge which relates to a drive device and which is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-331403. The leader pin separates from a case while being caught by a pull-out means which enters into the case. The operation of this pull-out means is complex. Thus, at the pull-out means, in addition to the above-described arm 224, there is the need for a complex mechanism for driving the catching portion which catches on the leader pin. In this way, in a conventional recording tape cartridge equipped with a leader pin, the structure of the drive device is complex.